Investigation of a wind model for cataclysmic variable ultraviolet resonance line emission.

Abstract

The present investigation of ionization and thermal structure in a spherically symmetric, radiatively driven wind emanating from the vicinity of a cataclysmic variable's white dwarf notes that wind ionization is always high for plausible wind and radiation field parameter values, and that resonance scattering dominates line formation at large radii. Theoretically derived line fluxes are compared with the results of IUE observations of the eclipsing, nova-like variables UX Uma and RW Tri, and the lack of significant UV resonance line eclipsing found suggests that the line-forming region is large by comparison with the secondary star dimensions in each of these systems. Observed continuum and line fluxes are not inconsistent with the line saturation that would be expected if the lines were formed by resonance scattering. It is concluded that the UV resonance lines observed in these spectra cannot form in a single volume.